Early-rain-resistant joint-sealing compounds

ABSTRACT

Early-rain-resistant joint-sealing compounds containing 
     (a) aqueous polymer dispersions (I), 
     (b) nonionic cellulose ethers (II) selected from the group consisting of hydroxyethyl, hydroxyethyl-methyl, hydroxypropyl-methyl and hydroxypropyl cellulose, 
     (c) fillers, and 
     (d) optionally typical additives, such as pigments, plasticizers, extenders, thickeners, foam inhibitors, dispersion aids, pH regulators, preservatives and anti-aging agents, 
     which can be produced by thorough mixing of (I) with the other constituents. To be able to introduce (II) in quantities above the solubility limit, the joint-sealing compounds are characterized in that (II) is added and intermixed in retarded form in admixture with the fillers.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application is a continuation-in-part of U.S. Ser. No. 07/342,408,filed Apr. 24, 1989, now U.S. Pat. No. 5,004,769.

This invention relates to early-rain-resistant joint-sealing compoundscontaining

(a) aqueous polymer dispersions (I),

(b) nonionic cellulose ethers (II) selected from the group consisting ofhydroxyethyl, hydroxyethyl-methyl, hydroxypropyl-methyl andhydroxypropyl cellulose,

(c) fillers, and

(d) optionally typical additives, such as pigments, plasticizers,extenders, thickeners, foam inhibitors, dispersion aids, pH regulators,preservatives and anti-aging agents, which can be produced by thoroughmixing of (I) with the other constituents; to a process for theproduction of these joint-sealing compounds and to their use.

2. Discussion of Related Art

Joint-sealing compounds are known to the expert and have beensuccessfully used in practice. Problems are involved in the use ofjoint-sealing compounds in applications where there is a possibility ordanger of the joint-sealing compound coming into contact with water, forexample spray water or rain, before curing. Thus, many of thejoint-sealing compounds hitherto used, including those designed foroutdoor application, are completely or partly washed out by heavyrainfall beginning shortly after their application. The use of nonioniccellulose ethers in joint-sealing or coating compounds based on acrylatedispersions is known from German Patent 38 14 078-A-1. The use ofcertain cellulose ethers in these compounds is said to improve washoutbehavior under the effect of water, such as rain water, and alsosmoothing behavior. The quantities in which the cellulose ethers areused in German Patent 38 14 078-A-1 are based on the solids content ofthe acrylate dispersion. There is no explicit reference to the ratio of"free" water to the cellulose ethers. Although it is clear from theExamples that the constituents mentioned were mixed in a planetary mixerfor the production of a joint-sealing compound, there is no indicationof the form or the order in which the individual constituents are mixedwith one another.

However, it has been found in practice that, with early-rain-resistantjoint-sealing compounds of the type in question, the individualconstituents cannot be added in just any order or in just any form inthe production of the joint-sealing compounds. For example, although thecellulose ethers mentioned can be scattered in small quantities intocertain polymer dispersions and dissolved therein on a laboratory scale,the same does not apply on a production scale and certainly not inquantities which, based on the "free" water, are too large to obtaincomplete dissolution. If such an attempt is made, clumping or breakingof the dispersion consistently occur. Although it is sometimes possibleto rehomogenize the cellulose ether clumps, it is not possible toredisperse dispersion particles once they have coagulated. It is alsonot apparent to the expert from German Patent 38 14 078-A-1 thatearly-rain-resistant joint-sealing compounds of the type in question canbe produced with other aqueous polymer dispersions than the acrylatedispersions mentioned therein.

Nonionic cellulose ethers are also known as constituents of coatingcompounds and paints, for example of the type based on aqueousdispersions of organopolysiloxanes, as described in German Patent 12 84007, or of the type based on vinyl acetate-maleic acid dibutyl esterdispersions, as described in German Patent 21 08 365. However, there isnothing in either of said applications to indicate to the expert thatcellulose ethers of the type in question would also be suitable forjoint-sealing compounds based on the same polymer dispersions as to leadto the desired effects.

A roof coating compound containing a polyacrylate dispersion as binderand hydroxyethyl cellulose as thickener in addition to fillers and otherauxiliaries is described in the journal Resin Review 35, 2. This coatingcompound is claimed to be particularly resistant to wash-out. However,this property is attributed to the special setting behavior of thepolyacrylate emulsion specially developed and used for coating compoundsof the type in question. Thus, it was not logical to the expert to usehydroxyethyl cellulose for improving early rain resistance injoint-sealing compounds.

In addition, coating compounds do not satisfy the demands made ofjoint-sealing compounds, more particularly as laid down in DIN 52 456"Bestimmung der Verarbeitbarkeit von Dichtstoffen (Determination of theProcessability of Sealants)" and in DIN 52 454 "Standvermgen(Stability)".

In regard to stability in particular, joint-sealing compounds, unlikecoating compounds, are required to have the property of running onlyslightly, if at all, from a U-profile filled with the compound which,after filling, is placed in an upright position. Coating compounds aregenerally of lower viscosity because, on the one hand, they are designedfor application by spray-coating or roll-coating and, on the other hand,are intended to show a certain flow for levelling of the compound.Although, in principle, joint-sealing compounds and coating compoundsmay be produced from the same constituents and although it should alsobe possible to produce a tolerably useful coating compound by dilutionof a joint-sealing compound, the converse does not necessarily apply.

It is known from Ullmann, Enzyklopadie der technischen Chemie, 4thEdition, Vol. 9, Verlag Chemie, Weinheim/Bergstraβe 1974, pages 208-209,that nonionic cellulose ether derivatives, such as hydroxyethylcellulose (HEC), hydroxyethyl-methyl cellulose (HEMC) andhydroxypropyl-methyl cellulose (HPMC), are used in polymeric plastersand emulsion paints inter alia for improving water retention power, opentime, wet adhesion and thickening and setting behavior. However, thereis nothing to indicate to the expert that cellulose ethers such as thesein joint-sealing compounds lead to an improvement in spreadability,smoothing behavior and resistance to spray water of uncured surfaces ofthese compounds. In addition, paints, such as emulsion paints, andpolymeric mortars are different materials from, and cannot be comparedwith, joint-sealing compounds. Thus, although polymeric plasters maypossibly be used for filling joints, they generally do not havepronounced sealing properties and, in contrast to joint-sealingcompounds, can be divided into portions and applied by trowel.

The problem addressed by the present invention was to providejoint-sealing compounds based on polymer dispersions which, in additionto good smoothing behavior, would show early rain resistance beforecuring without any adverse effect on other desirable properties, such asmodulus of elasticity, elongation at break and resilience, or onresistance to migration and freedom from coagulates and specks. Anotherproblem addressed by the invention was to provide a process which wouldenable compounds such as these to be produced.

DESCRIPTION OF THE INVENTION

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients or reaction conditions usedherein are to be understood as modified in all instances by the term"about".

The afore-mentioned problem was solved by early-rain-resistantjoint-sealing compounds containing

(a) aqueous polymer dispersions (I),

(b) nonionic cellulose ethers (II) selected from the group consisting ofhydroxyethyl, hydroxyethyl-methyl, hydroxypropyl-methyl andhydroxypropyl cellulose,

(c) fillers, and

(d) optionally typical additives, such as pigments, plasticizers,extenders, thickeners, foam inhibitors, dispersion aids, pH regulators,preservatives and anti-aging agents,

which can be produced by thorough mixing of (I) with the otherconstituents, wherein (II) is added and intermixed in retarded form inadmixture with the fillers.

The individual constituents of the joint-sealing compound are known assuch to the expert, for example from German Patent 38 14 078-A-1. Othersuitable polymer dispersions for the production of joint-sealingcompounds are commercially available and/or are known to the expert fromthe patent literature and from the specialist literature, cf. forexample E. Flick, Construction and Structural Adhesives and Sealants,Noyes Publications, Park Ridge 1988, or E. Flick, Adhesives and SealantCompound Formulations, Noyes Publications, Park Ridge 1978. Particularlyadvantageous joint-sealing compounds contain dispersions of film-formingpolyacrylates and/or acrylate copolymers. Other advantageousjoint-sealing compounds according to the invention are based ondispersions of film-forming polymers or copolymers selected from thegroup consisting of ethylene-vinyl acetate, butadiene-styrene, vinylacetate-maleic acid ester, silicone, urethane, vinyl acetate,methacrylic acid-chloroprene and isoprene polymers or copolymers.Different polymer dispersions may be combined. Polysulfide dispersionshave also proved to be particularly suitable in conjunction withfilm-forming polymers. In the interests of simplicity, the followingtext refers only to polymer dispersions.

Most of the constituents are commercially available. Thus, both retardedand non-retarded cellulose ethers are commercially available. Retardedcellulose ethers are understood to be cellulose ethers which, afterintroduction into water, swell with delay compared with the unretardedsubstances. This is achieved, for example, by crosslinking with glyoxalat the surface of the cellulose ether particles, as described forexample in German Patent 24 15 56.Whereas it has hitherto been standardpractice to introduce the cellulose ethers mentioned in aqueous solutionor in quantities which dissolve smoothly in the "free" water present inthe compounds, the joint-sealing compounds according to the inventionare distinguished by a new production process in regard to introductionof the cellulose ethers.

The retarded cellulose ethers are introduced in admixture with thefillers. To this end, these two constituents are thoroughly mixed withone another beforehand. Other solid constituents, for example pigments,may also be intermixed at the same time.

In one preferred process for the production of the joint-sealingcompounds according to the invention, finely divided cellulose ether inadmixture with the filler is added to and thoroughly mixed with thepolymer dispersion. Polymer dispersions having very high solids contentsmay optionally be slightly diluted beforehand. The pH regulators areadded last, the further additives being intermixed before and/or afteraddition of the filler.

The aqueous dispersions present in the joint-sealing compounds accordingto the invention preferably have solids contents of 40 to 75% by weightand, more preferably, 45 to 65% by weight. Their pH value may be atleast 6 and, preferably, is in the range from 7 to 9 and, if necessary,is adjusted to those values.

The cellulose ethers present in the joint-sealing compounds according tothe invention preferably have a Brookfield viscosity (2% aqueoussolution at 20° C.) of at least 5,000 mPa.s. It is preferred to usecellulose ethers having a viscosity of at least 25,000 mPa.s, i.e. forexample medium-viscosity hydroxyethyl celluloses. Particularly suitablecellulose ethers are so-called high-viscosity cellulose ethers whichhave a corresponding value of at least 70,000 mPa.s, for examplehigh-viscosity hydroxyethyl cellulose. Commercially availablehigh-viscosity hydroxyethyl cellulose has a viscosity of 100,000 mPa.s,for example in the form of a 2% aqueous solution at 20° C.

According to manufacturers' specifications, complete solutions cannot beobtained with hydroxyethyl cellulose, for example Natrosol 250 HHR, at aviscosity above 200,000 mPa.s. With the less hydrophilic celluloseethers suitable for use in accordance with the invention, this limit iseven lower, for example around 150,000 mPa.s for hydroxypropyl celluloseor at around 100,000 mPa.s for hydroxypropyl methyl cellulose. Gel-likepastes are formed to an increasing extent with increasing concentration.However, this seems to play a particular role in the early rainresistance of the joint-sealing compounds according to the invention.Although the exact mechanism involved has not been elucidated, it maynevertheless be assumed that, if this solubility limit is exceeded, anincreasing buildup of a gel-like structure partly contributes towardsthe compounds remaining resistant or substantially resistant to wash outby water, such as rain, before curing.

A key factor in this regard is evidently the quantitative ratio ofcellulose ether to "free" water which determines whether or not thissolubility limit is exceeded. In the present context, "free" water isthe water present in the sealing compound which is available to thecellulose ethers to dissolve therein. Accordingly, the total watercontent of the joint-sealing compound cannot be used for a correspondingcalculation. On the contrary, it is important to take into account thefact that the other constituents also require a certain amount of wateror bind in more or less solid form. Thus, so-called water values areknown for most fillers. In the case of heavy spar for example, the watercontent is 11 g water per 100 g heavy spar. For silica, for example ofthe HDK V 15 type (Wacker-Chemie), the water values are 350 to 400 g per100 g silica. Values such as these provide the expert with an indicationof the quantities of "bound" water which must be subtracted from thetotal water content of sealing compound to obtain the quantity of "free"water. Accordingly, this quantity of "free" water in relation to thequantity of the particular type of cellulose ether used shouldpreferably give a ratio which lies above the particular solubilitylimit.

The situation becomes somewhat more complicated when the expert has toallow for a water demand which arises when the dispersed polymerscontain salt-forming groups. Where an additional water demand such asthis arises, the expert may have to consult the relevant manufacturer'sspecifications, may have to estimate this demand on the basis ofempirical values or may have to determine it within approximate limitsby simple small-scale tests. In cases where it is intended to produce ajoint-sealing compound in which the solubility limit mentioned isexceeded, the cellulose ether cannot be added in the usual form, i.e. inthe form of a solution. The process according to the invention providesa method of producing such joint-sealing compounds.

In addition, the joint-sealing compounds according to the invention maycontain fillers in a quantity of 2 to 60% by weight and preferably in aquantity of 35 to 60% by weight, based on the total weight of thejoint-sealing compounds. Compounds such as these may have a certaintransparency where they contain only very little filler. Low fillercontents may be present in particular in compounds in which the fillershave an additional thickening effect, as in the case of silica. Iffillers which do not have this additional effect are used as solefillers, their content is generally between 35 and 60% by weight. Inthis case, the compounds are referred to as highly filled compounds.

In another advantageous embodiment of the invention, the joint-sealingcompounds contain chlorinated hydrocarbons, more particularlychlorinated paraffins, as plasticizers and nonionic surfactants aswetting agents. Commercially available chlorinated paraffins having achain length of about 10 to 18 carbon atoms and a chlorine content offrom about 40 to 70% by weight are preferred.

In one preferred embodiment, the joint-sealing compounds contain

(a) 25 to 90% by weight polymer dispersion, in the case of highly filledjoint-sealing compounds, more particularly, 25 to 40% by weight polymerdispersion,

(b) 2 to 60% by weight, and more particularly, 35 to 60% by weight,fillers,

(c) 0 to 1% by weight, and more particularly 0.3 to 0.5% by weight,wetting agents,

(d) 0 to 20% by weight, and more particularly, 5 to 15% by weight,plasticizers,

(e) 0 to 10% by weight, and more particularly, 4 to 6% by weight, othertypical additives, such as thickeners, foam inhibitors and pigments, and

(f) up to 1.5 % by weight cellulose ethers, all percentages by weightbased in each case on the total quantity.

The cellulose ether content should be not much less than 0.1% by weight.Good results are obtained in particular with joint-sealing compounds inwhich the cellulose ether content is between about 0.1 and 0.5% byweight, based on the total quantity, taking into account such basicparameters as the type of cellulose ether and the free water content.

In addition, the pH regulators, particularly the bases, are preferablyadded after the cellulose ethers in the production of the joint-sealingcompound. This is particularly advantageous in the case of retardedcellulose ethers because the retardation is eliminated more quickly inthe basic range. On the other hand, a neutral to basic pH value of thejoint-sealing compounds can have a favorable effect on their stability,particularly their shear stability.

To prevent air from being stirred in and to prevent air bubbles formingin the product, stirring may be carried out in vacuo.

The joint-sealing compounds are preferably used as directed. They areparticularly suitable for use in applications where they are exposedbefore curing to spray water, rain and the like.

The invention is illustrated by the following Examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The materials described in the examples as well as additional materialsproduced for comparison purposes were subjected to a wash-out test inwhich a sprinkling apparatus as seen in FIG. 1 was used. The sameapparatus is shown in side view in FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

The water spraying apparatus consists of a housing of transparentplastic having the following dimensions: height 70 cm, width 60 cm anddepth 60 cm. It comprises a housing 1, a shower head 2, a sample dish 3,a pump 4, a bottom outlet 5 and a shutoff cock 6 for the outlet. Thesample dish consists of a receptacle measuring 7×7 cm for a depth of 2.5cm. The shower head was a standard hand shower of the type used forpersonal hygiene and was adjusted in such a way that the sample wasuniformly sprayed with water. The distance between the sample dish 3 andshower head 2 was 30 cm.

The water spraying apparatus was operated with demineralized water, anexcess pressure of about 0.5 bar being produced by the pump. The waterthroughput was 300 1/h. The sample was sprayed with water for 5 minutesabout 1 minute after introduction and smoothing of the surface of thecompounds to be tested. The wash-out (in % by weight) was the differencein weight before and after spraying with water.

Processability was measured in accordance with DIN 52 456 using a 4 mmbore, a pressure of 2 bar and a test volume of 200 ml.

The compounds described in the Examples were also tested for theirsmoothing behavior. This test, which involved seven people workingindependently of one another, was carried out by applying a 30 cm longstrand of compound to a smooth, flat, dark surface and then smoothingthe strand thus applied with a spatula and with the fingers. Thesmoothing behavior was marked on a scale of 1 (=very good) to 6(=inadequate).

EXAMPLE 1

The following constituents were intensively mixed for a total of about30 minutes in a planetary mixer:

    ______________________________________                                        1,200 g commercially available aqueous dispersion of an                               acrylate copolymer containing approx. 55% by                                  weight solids and free carboxy groups (trade                                  name: Primal E 1785),                                                 200 g   polybutene as extender,                                               20 g    ethylene oxide adduct as wetting agent,                               4 g     commercially available halogenated preservative                               (AKTIZID TL 526),                                                     200 g   butyl benzyl phthalate as plasticizer,                                200 g   water,                                                                80 g    aliphatic low-aromatic solvent (SHELLSOL D 60),                       4 g     high-viscosity hydroxyethyl cellulose (NATROSOL                               250 HHR),                                                             2,040 g uncoated chalk,                                                       40 g    titanium dioxide, and                                                 12 g    25% aqueous ammonia solution.                                         ______________________________________                                    

The dispersion was introduced first. The polybutene, the ethylene oxideadduct, the preservative, the plasticizer, the water and the solventwere then added over a period of about 5 minutes with intensive mixing.The chalk and the titanium dioxide were then mixed with the hydroxyethylcellulose and incorporated in the mixture, followed by stirring for 10minutes. After addition of the ammonia, the mixture was stirred in avacuum of 40 mbar for another 15 minutes until it was smooth.

    ______________________________________                                        Processability according to DIN 52 456:                                                               1,000 g/min.                                          Smoothing behavior:     good                                                  Wash-out:               4.3% loss                                             ______________________________________                                    

EXAMPLE 2

The following constituents were intensively mixed for about 45 minutesin a planetary mixer:

    ______________________________________                                        1,750 g commercially available aqueous polybutyl acrylate                             dispersion (solids content approx. 62%) having a pH                           value of 6.0 to 6.5, a glass transition temperature                           Tg of -50° C., a viscosity of approx. 250 mPa ·               s                                                                             at 23° C. and an average particle size of 0.4 μm,           250 g   chloroparaffin (C.sub.12-14, 49% chlorine),                           2,800 g barium sulfate (trade name: Schwerspat EWO),                          100 g   titanium dioxide (trade name: KRONOS RN 56),                          25 g    sodium carbonate (technically pure commercial                                 product),                                                             25 g    ethylene oxide adduct (approx. 9.5 EO with nonyl-                             phenol),                                                              5 g     commercially available halogenated preservative,                      37 g    hydroxyethyl cellulose having a viscosity of                                  approx. 4,000 mPa · s (1% aqueous solution at                        20°                                                                    C.) and a hydroxyethyl group content of 55% by                                weight (trade name: Natrosol 250 HHR).                                ______________________________________                                    

The polymer dispersion was introduced first. The ethylene oxide adduct(emulsifier), the preservative and the chloroparaffin were then added.The hydroxyethyl cellulose was then thoroughly mixed with the bariumsulfate (filler) and the titanium dioxide and incorporated in this formin the mixture. After addition of the sodium carbonate in the form of a10% aqueous solution, the product was again thoroughly mixed in vacuo.

    ______________________________________                                        Processability according to DIN 52 456:                                                               2,260 g/min.                                          Smoothing behavior:     good                                                  Wash-out:               1% loss                                               ______________________________________                                    

When a total of 50 g of the same hydroxyethyl cellulose was added thefollowing results were obtained:

    ______________________________________                                        Processability according to DIN 52 456:                                                               1,300 g/min.                                          Smoothing behavior:     very good                                             Wash-out:               0.3% loss                                             ______________________________________                                    

EXAMPLE 3

The following constituents were intensively mixed for about 40 minutesin a planetary mixer:

    ______________________________________                                        1,400 g                                                                              commercially available aqueous polybutyl acrylate                             dispersion (solids content approx. 62%) having a pH                           value of 6.0 to 6.5, a glass transition temperature                           Tg of -50° C., a viscosity of approx. 250 mPa · s             at 23° C. and an average particle size of 0.4 μm,            200 g  polybutene,                                                            12 g   ethylene oxide adduct (approx. 9.5 EO with nonyl-                             phenol),                                                               8 g    commercially available halogenated preservative,                       10 g   sodium carbonate (technically pure commercial                                 product),                                                              146 g  tapwater,                                                              20 g   hydroxyethyl cellulose having a viscosity of                                  approx. 4,000 mPa · s (1% aqueous solution at 20°             C.)                                                                           and a hydroxyethyl group content of 55% by weight                             (trade name: Natrosol 250 HHR),                                        80 g   titanium dioxide,                                                      1,008 g                                                                              barium sulfate (Schwerspat EWO),                                       1,096 g                                                                              calcium carbonate (Omega BLP 3),                                       20 g   hydrocarbons (Bp. 180-210° C., such as Kristallol               ______________________________________                                               60)                                                                

The polymer dispersion was introduced first. The ethylene oxide adduct(emulsifier), the preservative, the polybutene and the Kristallol werethen thoroughly mixed with one another. The chalk, the titanium dioxideand the barium sulfate were then mixed with the hydroxyethyl celluloseand incorporated in the mixture, followed by stirring for 10 minutes.After addition of the sodium carbonate dissolved in water, the productwas stirred in vacuo for another minutes until it was smooth.

    ______________________________________                                        Processability according to DIN 52 456:                                                               2,830 g/min.                                          Smoothing behavior:     good                                                  Wash-out:               1.7% loss                                             ______________________________________                                    

What is claimed is:
 1. In the process of preparing anearly-rain-resistant joint-sealing composition consisting essentially ofadding to a mixing vessel(a) 25 to 90% by weight of an aqueousdispersion containing from about 40 to about 75% by weight offilm-forming polymers or copolymers selected from the group consistingof ethylene-vinyl acetate, butadiene-styrene, vinyl acetate-meleic acidester, silicone, urethane, vinyl acetate, methacrylic acid-chloroprene,isoprene, polysulfide, acrylate and polyacrylate; (b) adding to saidvessel from 0 to about 1% by weight of a wetting agent; (c) adding tosaid vessel from 0 to about 20% by weight of a plasticizer; (d) addingto said vessel from 0 to 10% by weight of an additive selected from athickener, foam inhibitor, and pigment; the improvement comprising (e)mixing from about 2 to about 60% by weight of a filler with from about0.1 to about 1.5% by weight of a nonionic cellulose ether in retardedform selected from the group consisting of hydroxyethyl cellulose,hydroxyethyl-methyl cellulose, hydroxypropyl-methyl cellulose andhydroxypropyl cellulose having a Brookfield viscosity in a 2% aqueoussolution at about 20° C. of at least about 5,000 mPa.s, based on theweight of said composition; and (f) adding the mixture prepared in step(e) to said vessel followed by thorough mixing of the composition. 2.The process as in claim 1 wherein the ratio of said nonionic celluloseether to free water is selected so that said cellulose ether is notcompletely dissolved in said free water.
 3. The process as in claim 1wherein said nonionic cellulose ether has a Brookfield viscosity in a 2%aqueous solution at about 20° C. of at least about 70,000 mPa.s.
 4. Theprocess as in claim 1 wherein said plasticizer comprises a chlorinatedhydrocarbon.
 5. The process as in claim 4 wherein said chlorinatedhydrocarbon comprises chlorinated paraffin.
 6. The process as in claim 1including (g) adding to said composition a pH regulator.
 7. In anearly-rain-resistant joint-sealing composition prepared by adding to amixing vessel(a) from about 25 to about 90% by weight of an aqueousdispersion containing from about 40 to about 75% by weight offilm-forming polymers or copolymers selected from the group consistingof ethylene-vinyl acetate, butadiene-styrene, vinyl acetate-maleic acidester, silicone, urethane, vinyl acetate, methacrylic acid-chloroprene,isoprene, polysulfide, acrylate and polyacrylate; (b) adding to saidvessel from 0 to about 1% by weight of a wetting agent, (c) adding tosaid vessel from 0 to about 20% by weight of a plasticizer, (d) addingto said vessel from 0 to 10% by weight of a thickener, foam inhibitor,and pigment, the improvement comprising (e) mixing from about 2 to about60% by weight of a filler with from about 0.5 to about 6% by weight of anonionic cellulose ether in retarded form selected from the groupconsisting of hydroxyethyl cellulose, hydroxyethyl-methyl cellulose,hydroxypropyl-methyl cellulose and hydroxypropyl cellulose having aBrookfield viscosity in a 2% aqueous solution at about 20° C. of atleast about 5,000 mPa.s, based on the weight of said composition; and(f) adding the mixture prepared in step (e) to said vessel followed bythorough mixing of the composition.
 8. A composition as in claim 7wherein the ratio of said nonionic cellulose ether to free water isselected so that said cellulose ether is not completely dissolved insaid free water.
 9. A composition as in claim 7 wherein said nonioniccellulose ether has a Brookfield viscosity in a 2% aqueous solution atabout 20° C. of at least about 70,000 mPa.,s.
 10. A composition as inclaim 7 wherein said plasticizer comprises a chlorinated hydrocarbon.11. A composition prepared as in claim 7 including (g) adding to saidcomposition a pH regulator.
 12. A composition as in claim 10 whereinsaid chlorinated hydrocarbon comprises chlorinated paraffin.
 13. In aprocess for sealing a joint or a gap in a building structure exposed torain or water before a sealing compound is cured, comprising applying tosaid joint or gap an early-rain-resistant joint-sealing compositionprepared by adding to a mixing vessel(a) an aqueous dispersioncontaining from about 40 to about 75% by weight of film-forming polymersor copolymers selected from the group consisting of ethylene-vinylacetate, butadiene-styrene, vinyl acetate-maleic acid ester, silicone,urethane, vinyl acetate, methacrylic acid-chloroprene, isoprene,polysulfide, acrylate and polyacrylate; (b) adding to said vessel from 0to about 1% by weight of a wetting agent, (c) adding to said vessel from0 to about 20% by weight of a plasticizer, (d) adding to said vesselfrom 0 to 10% by weight of a thickener, foam inhibitor, and pigment, theimprovement comprising (e) mixing from about 2 to about 60% by weight ofa filler with from about 0.1 to about 1.5% by weight of a nonioniccellulose ether in retarded form selected from the group consisting ofhydroxyethyl cellulose, hydroxyethyl-methyl cellulose,hydroxypropyl-methyl cellulose and hydroxypropyl cellulose having aBrookfield viscosity in a 2% aqueous solution at about 20° C. of atleast about 5,000 mPa.s, based on the weight of said composition; and(f) adding the mixture prepared in step (e) to said vessel followed bythorough mixing of the composition.
 14. A process as in claim 13 whereinthe ratio of said nonionic cellulose ether to free water is selected sothat said cellulose ether is not completely dissolved in said freewater.
 15. A process as in claim 13 wherein said nonionic celluloseether has a Brookfield viscosity in a 2% aqueous solution at about 20°C. of at least about 70,000 mPa.s.
 16. A process as in claim 13 whereinsaid plasticizer comprises a chlorinated hydrocarbon.
 17. A process asin claim 16 wherein said chlorinated hydrocarbon comprises chlorinatedparaffin.
 18. A process as in claim 13 including (h) adding to saidcomposition a pH regulator.